1. Field of the Invention
The present invention relates to an apparatus for interengaging or mating a pair of rows of slide fastener coupling elements respectively formed from a pair of continuous plastic filaments into a zigzag shape.
2. Prior Art
To manufacture a pair of elongate slide fastener stringers each having a row of continuous zigzag coupling elements, it has been customary to shape a continuous thermoplastic synthetic resin monofilament into a row of zigzag coupling elements by means of a heated die wheel, then to attach by sewing two such rows of coupling elements to a pair of stringer tapes along their opposed edges, then to pair the rows of coupling elements into a chain of coupling elements, and finally to mount top and bottom end stops and sliders on the coupling element chain. For the purposes of increasing rate of production, there has been a need for a machine that can pair the rows of coupling elements before being sewn to the stringer tapes. Many attempts have been made to devise such a pairing machine, however, the results have been unsatisfactory in that the coupling elements formed from a plastic monofilament would be easily deformed under compressing or tensioning force applied as they are interengaged.